import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.KeyEvent;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.Gallery;
public class MyActivity extends Activity implements OnItemClickListener{public static HashMap<String,Bitmap> imagesCache=new HashMap<String, Bitmap>(); //图片缓存private Gallery images_ga;public static ImageAdapter imageAdapter;private int num=0;List<String> urls = new ArrayList<String>(); //所有图片地址ListList<String> url = new ArrayList<String>(); //需要下载图片的url地址@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.gallery_1);Files.mkdir(this);init();}private void init(){Bitmap image= BitmapFactory.decodeResource(getResources(),R.drawable.default_movie_post);imagesCache.put("background_non_load",image);       //设置缓存中默认的图片images_ga = (Gallery) findViewById(R.id.gallery);urls.add("http://hiphotos.baidu.com/baidu/pic/item/f603918fa0ec08fabf7a641659ee3d6d55fbda0d.jpg");urls.add("http://hiphotos.baidu.com/baidu/pic/item/43a7d933c895d143d011bf9273f082025aaf071f.jpg");urls.add("http://hiphotos.baidu.com/baidu/pic/item/63d0f703918fa0ec2ebf584b269759ee3d6ddb7f.jpg");urls.add("http://hiphotos.baidu.com/baidu/pic/item/5ab5c9ea15ce36d31ed8387f3af33a87e850b1a5.jpg");urls.add("http://hiphotos.baidu.com/baidu/pic/item/8601a18b87d6277f6e46217628381f30e924fc2c.jpg");urls.add("http://hiphotos.baidu.com/baidu/pic/item/b48f8c54acf9964c3a29350e.jpg");urls.add("http://hiphotos.baidu.com/baidu/pic/item/bd3eb13533fa828b48da6aabfd1f4134960a5af9.jpg");urls.add("http://hiphotos.baidu.com/baidu/pic/item/29381f30e924b899da3ce5706e061d950a7bf672.jpg");urls.add("http://hiphotos.baidu.com/baidu/pic/item/bd3eb13533fa828b48da6aabfd1f4134960a5af9.jpg");urls.add("http://hiphotos.baidu.com/baidu/pic/item/4bed2e738bd4b31cd73d63fd87d6277f9e2ff877.jpg");urls.add("http://hiphotos.baidu.com/baidu/pic/item/caef76094b36acaf92b619b87cd98d1001e99c24.jpg");urls.add("http://hiphotos.baidu.com/baidu/pic/item/8435e5dde71190efd6154d95ce1b9d16fcfa608a.jpg");urls.add("http://hiphotos.baidu.com/baidu/pic/item/b3de9c824ba1d4cd6d81190f.jpg");urls.add("http://hiphotos.baidu.com/baidu/pic/item/e0fe9925cc2c683834a80f11.jpg");urls.add("http://hiphotos.baidu.com/baidu/pic/item/0bd162d9f2d3572c65911a988a13632762d0c307.jpg");urls.add("http://hiphotos.baidu.com/baidu/pic/item/ac6eddc451da81cb2ac1708a5266d01609243155.jpg");urls.add("http://hiphotos.baidu.com/baidu/pic/item/1bd5ad6e8416d98080cb4a48.jpg");urls.add("http://hiphotos.baidu.com/baidu/pic/item/3c6d55fbb2fb43169d0508ca20a4462309f7d36c.jpg");urls.add("http://hiphotos.baidu.com/baidu/pic/item/faedab64034f78f0daf3664a79310a55b2191c8a.jpg");urls.add("http://hiphotos.baidu.com/baidu/pic/item/2fdda3cc7cd98d10b05af088213fb80e7aec90f9.jpg");urls.add("http://hiphotos.baidu.com/baidu/pic/item/b8014a90f603738d9536f39bb31bb051f819ec0f.jpg");urls.add("http://hiphotos.baidu.com/baidu/pic/item/2fdda3cc7cd98d10b05af088213fb80e7aec90f9.jpg");imageAdapter = new ImageAdapter(urls, this);images_ga.setAdapter(imageAdapter);images_ga.setOnItemClickListener(this);images_ga.setOnItemSelectedListener(new OnItemSelectedListener() {@Overridepublic void onItemSelected(AdapterView<?> arg0, View arg1, int arg2, long arg3) {num=arg2;Log.i("mahua", "ItemSelected=="+arg2);GalleryWhetherStop();}@Overridepublic void onNothingSelected(AdapterView<?> arg0) {// TODO Auto-generated method stub}});}@Override
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) {Log.i("GOLF", "第"+arg2+"个被点击了");
}/*** 判断Gallery滚动是否停止,如果停止则加载当前页面的图片*/private void GalleryWhetherStop() {Runnable runnable = new Runnable() {public void run() {try {int index =0;index = num;Thread.sleep(1000);if (index == num) {url.add(urls.get(num));if(num!=0 && urls.get(num-1)!=null) {url.add(urls.get(num-1));}if(num!=urls.size()-1 && urls.get(num+1)!=null) {url.add(urls.get(num+1));}Message m = new Message();m.what = 1;mHandler.sendMessage(m);}} catch (Exception e) {e.printStackTrace();}}};new Thread(runnable).start();
}// 加载图片的异步任务class LoadImageTask extends AsyncTask<String, Void, Bitmap> {@Override  protected void onCancelled() {  // TODO Auto-generated method stub  super.onCancelled();  }  @Override  protected void onPostExecute(Bitmap result) {  // TODO Auto-generated method stub        super.onPostExecute(result);  }  @Overrideprotected Bitmap doInBackground(String... params) {Bitmap bitmap = null;try {String url = params[0];boolean isExists = Files.compare(url); //这里是自己写的工具类，判断本地缓存是否已经下载过图片if (isExists == false) {//如果不存在就去下载图片Net net = new Net();byte[] data = net.downloadResource(MyActivity.this, url);bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);imagesCache.put(url, bitmap); // 把下载好的图片保存到缓存中Files.saveImage(url, data);} else {//如果存在直接读取缓存图片byte[] data = Files.readImage(url);bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);imagesCache.put(url, bitmap); // 把下载好的图片保存到缓存中}Message m = new Message();//图片加载完成通知重新加载m.what = 0;mHandler.sendMessage(m);} catch (Exception e) {e.printStackTrace();}return bitmap;}}private Handler mHandler = new Handler() {public void handleMessage(Message msg) {try {switch (msg.what) {case 0: {imageAdapter.notifyDataSetChanged();break;}case 1: {for(int i=0; i<url.size(); i++) {LoadImageTask task = new LoadImageTask();//异步加载图片task.execute(url.get(i));Log.i("mahua", url.get(i));}url.clear();}}super.handleMessage(msg);} catch (Exception e) {e.printStackTrace();}}
};
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {if(keyCode==KeyEvent.KEYCODE_BACK){System.exit(0);}return super.onKeyDown(keyCode, event);
}
}import java.util.List;
import android.content.Context;
import android.content.res.AssetManager;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageView;public class ImageAdapter extends BaseAdapter {
public static final BaseAdapter Adapter = null;
private List<String> imageUrls; // 图片地址list
private Context context;
int mGalleryItemBackground;public ImageAdapter(List<String> imageUrls, Context context) {
this.imageUrls = imageUrls;
this.context = context;
// /*
// * 使用在res/values/attrs.xml中的<declare-styleable>定义 的Gallery属性.
// */
TypedArray a = context.obtainStyledAttributes(R.styleable.Gallery1);
/* 取得Gallery属性的Index id */
mGalleryItemBackground = a.getResourceId(
R.styleable.Gallery1_android_galleryItemBackground, 0);
/* 让对象的styleable属性能够反复使用 */
a.recycle();
}
public int getCount() {
return imageUrls.size();
}
public Object getItem(int position) {
return imageUrls.get(position);
}
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
Bitmap image;
ImageView view = new ImageView(context);
image = MyActivity.imagesCache.get(imageUrls.get(position));
// 从缓存中读取图片
if (image == null) {
image = MyActivity.imagesCache.get("background_non_load");
}
// 设置所有图片的资源地址
view.setImageBitmap(image);
view.setScaleType(ImageView.ScaleType.FIT_XY);
view.setLayoutParams(new Gallery.LayoutParams(240, 320));
view.setBackgroundResource(mGalleryItemBackground);
/* 设置Gallery背景图 */
return view;
}
}attrs.xml
<?xml version="1.0" encoding="utf-8"?>
<resources>
<declare-styleable name="TogglePrefAttrs">
<attr name="android:preferenceLayoutChild" />
</declare-styleable><!-- These are the attributes that we want to retrieve from the theme
in view/Gallery1.java -->
<declare-styleable name="Gallery1">
<attr name="android:galleryItemBackground" />
</declare-styleable><declare-styleable name="LabelView">
<attr name="text" format="string" />
<attr name="textColor" format="color" />
<attr name="textSize" format="dimension" />
</declare-styleable>
</resources>